Molded products, such as plastics, and the like, have been known for decades and are used, inter alia, for product packaging, product presentation, material storage, and the like. Because of their widely-varying nature and characteristics, energy efficient methods of producing these items are a necessity. Of particular interest are methods to quickly cool a molded product, particularly within the context of manufacturing facilities.
Previous methods of cooling, while effective in cooling a product of interest, are wasteful in failing to recapture heat lost during processing. Rather than being reused, the heat was entirely lost, thus increasing energy costs by requiring more heat in earlier processing steps. Known systems and methods are largely inefficient, thereby increasing operating costs of molding and manufacturing molded products.
Early cooling methods included the application of either ambient air from a fan or compressed air blown across the molded product immediately after molding. These convective cooling methods removed heat from the molded product. The removed heat, however, was not contained within a closed system, but was wastefully lost. Thus, while the molding method achieved its objective, it was largely inefficient, as additional energy was required to create the required heat in earlier processing steps.
U.S. Pat. No. 4,657,574 discloses cooling molded glass using a rod-shaped material of higher thermal conductivity than the mold. Specifically, the rod-shaped material extends through the mold in a position proximate to the heated product, where the rod is able to extract heat from the heated product and then withdraw into a recess. This apparatus and method are largely inefficient because the heat extracted from the resulting product is not reused within the system but is lost.
U.S. Pat. Nos. 4,313,751; 5,398,745; 5,824,237; and 7,303,387 disclose alternative methods of cooling a molded product using convective fluid flow. Specifically, each of these patents discloses a molding machine with one or more channels passing through the mold, proximate to the heated product. A cooling medium, e.g. water, may be passed through these channels and, ultimately, through the mold itself. As it passes through the mold, the cooling medium extracts heat from the molded product that is in the mold using convective cooling mechanisms. While these approaches appropriately cool the heated product, they do not use the extracted heat in any way. Rather, the heat is largely lost, providing inefficiency within the system.
U.S. Pat. No. 3,748,866 discloses an alternative wherein a heated product is cooled using a larger refrigeration system. A first loop of circulated cooling fluid passes through channels of the mold and through a heat exchanger. As the fluid of the first loop passes through the mold, the fluid receives heat, thereby cooling the molded product. The heated fluid then passes into a heat exchanger in which fluid from a second coolant loop extracts the heat from the first loop. The fluid from the first loop is then recirculated back through the mold and the fluid from the second loop is provided to a compressor and an associated condenser, where it is cooled and recirculated to the heat exchanger. While this system uses multiple processing steps to provide a circulation system for lowering the temperature of the mold, there is no reapplication of the captured heat back to the molding process. Thus, this system does not maximize efficiency of a molding method.
Based on the foregoing, apparatus and methods for cooling a molded product with little to no loss of the recaptured heat are desirable. Apparatus and methods are further desirable that recapture heat from the molded product and apply that heat to one or more earlier steps in the molding process. Finally, apparatus and methods are desirable for extracting heat from the molded product and reapplying that heat to un-molded resin such that the resin is heated prior to being molded.
This invention addresses these needs.